lsquic_parse.h revision 084338b1 
1/* Copyright (c) 2017 - 2021 LiteSpeed Technologies Inc.  See LICENSE. */
2#ifndef LSQUIC_PARSE_H
3#define LSQUIC_PARSE_H 1
4
5#include <stdint.h>
6
7#include "lsquic_packet_common.h"
8#include "lsquic_packet_gquic.h"
9
10struct lsquic_conn;
11struct lsquic_packet_in;
12struct lsquic_packet_out;
13struct packin_parse_state;
14struct stream_frame;
15struct lsquic_cid;
16enum packet_out_flags;
17enum lsquic_version;
18enum stream_dir;
19
20
21struct ack_info
22{
23    enum packnum_space pns;
24    enum {
25        AI_ECN        = 1 << 0, /* ecn_counts[1,2,3] contain ECN counts */
26        AI_TRUNCATED  = 1 << 1, /* There were more ranges to parse, but we
27                                 * ran out of elements in `ranges'.
28                                 */
29    }               flags;
30    unsigned    n_ranges;       /* This is at least 1 */
31                                /* Largest acked is ack_info.ranges[0].high */
32    lsquic_time_t   lack_delta;
33    uint64_t        ecn_counts[4];
34    struct lsquic_packno_range ranges[256];
35};
36
37#define largest_acked(acki) (+(acki)->ranges[0].high)
38
39#define smallest_acked(acki) (+(acki)->ranges[(acki)->n_ranges - 1].low)
40
41/* Chrome may send an empty ACK frame when it closes a connection.
42 * We do not know why it occurs -- perhaps a bug in Chrome.
43 */
44/* This macro cannot be used in IETF QUIC as zero is a valid packet number.
45 * Hopefully the Chrome bug will have been fixed by then.
46 */
47#define empty_ack_frame(acki) (largest_acked(acki) == 0)
48
49/* gaf_: generate ACK frame */
50struct lsquic_packno_range;
51typedef const struct lsquic_packno_range *
52    (*gaf_rechist_first_f)          (void *rechist);
53typedef const struct lsquic_packno_range *
54    (*gaf_rechist_next_f)           (void *rechist);
55typedef lsquic_time_t
56    (*gaf_rechist_largest_recv_f)   (void *rechist);
57
58/* gsf_: generate stream frame */
59typedef size_t (*gsf_read_f) (void *stream, void *buf, size_t len, int *fin);
60
61/* This structure contains functions that parse and generate packets and
62 * frames in version-specific manner.  To begin with, there is difference
63 * between GQUIC's little-endian (Q038 and lower) and big-endian formats
64 * (Q039 and higher).  Q046 and higher uses different format for packet headers.
65 */
66struct parse_funcs
67{
68    /* Return buf length */
69    int
70    (*pf_gen_reg_pkt_header) (const struct lsquic_conn *,
71                const struct lsquic_packet_out *, unsigned char *, size_t,
72                /* In Q050 and IETF QUIC, these are set: */
73                unsigned *packno_off, unsigned *packno_len);
74    void
75    (*pf_parse_packet_in_finish) (struct lsquic_packet_in *packet_in,
76                                                struct packin_parse_state *);
77    enum quic_frame_type
78    (*pf_parse_frame_type) (const unsigned char *, size_t);
79    /* Return used buffer length or a negative value if there was not enough
80     * room to write the stream frame.  In the latter case, the negative of
81     * the negative return value is the number of bytes required.  The
82     * exception is -1, which is a generic error code, as we always need
83     * more than 1 byte to write a STREAM frame.
84     */
85    /* pf_gen_stream_frame and pf_gen_crypto_frame must be adjacent so that
86     * they can be cast to an array.
87     */
88    int
89    (*pf_gen_stream_frame) (unsigned char *buf, size_t bufsz,
90                            lsquic_stream_id_t stream_id, uint64_t offset,
91                            int fin, size_t size, gsf_read_f, void *stream);
92    /* The two "UNUSED" parameters are here so that it matches
93     * pf_gen_stream_frame.
94     */
95    int
96    (*pf_gen_crypto_frame) (unsigned char *buf, size_t bufsz,
97                            lsquic_stream_id_t UNUSED_1, uint64_t offset,
98                            int UNUSED_2, size_t size, gsf_read_f, void *stream);
99    /* pf_parse_stream_frame and pf_parse_crypto_frame must be adjacent so that
100     * they can be cast to an array.
101     */
102    int
103    (*pf_parse_stream_frame) (const unsigned char *buf, size_t rem_packet_sz,
104                                                    struct stream_frame *);
105    int
106    (*pf_parse_crypto_frame) (const unsigned char *buf, size_t rem_packet_sz,
107                                                    struct stream_frame *);
108    /* Return true if STREAM frame extends to the end of the packet and thus
109     * does not contain a Length field (no update).
110     */
111    int
112    (*pf_dec_stream_frame_size) (unsigned char *buf, size_t new_size);
113    int
114    (*pf_parse_ack_frame) (const unsigned char *buf, size_t buf_len,
115                                    struct ack_info *ack_info, uint8_t exp);
116    int
117    (*pf_gen_ack_frame) (unsigned char *outbuf, size_t outbuf_sz,
118                gaf_rechist_first_f, gaf_rechist_next_f,
119                gaf_rechist_largest_recv_f, void *rechist, lsquic_time_t now,
120                int *has_missing, lsquic_packno_t *largest_received,
121                const uint64_t *ecn_counts);
122    int
123    (*pf_gen_stop_waiting_frame) (unsigned char *buf, size_t buf_len,
124                    lsquic_packno_t cur_packno, enum packno_bits,
125                    lsquic_packno_t least_unacked_packno);
126    int
127    (*pf_parse_stop_waiting_frame) (const unsigned char *buf, size_t buf_len,
128                     lsquic_packno_t cur_packno, enum packno_bits,
129                     lsquic_packno_t *least_unacked);
130    int
131    (*pf_skip_stop_waiting_frame) (size_t buf_len, enum packno_bits);
132    int
133    (*pf_gen_window_update_frame) (unsigned char *buf, int buf_len,
134                                lsquic_stream_id_t stream_id, uint64_t offset);
135    int
136    (*pf_parse_window_update_frame) (const unsigned char *buf, size_t buf_len,
137                              lsquic_stream_id_t *stream_id, uint64_t *offset);
138    /* The third argument for pf_gen_blocked_frame() and pf_parse_blocked_frame()
139     * is Stream ID for GQUIC and offset for IETF QUIC.  Since both of these are
140     * uint64_t, we'll use the same function pointer.  Just have to be a little
141     * careful here.
142     */
143    int
144    (*pf_gen_blocked_frame) (unsigned char *buf, size_t buf_len,
145                                                lsquic_stream_id_t stream_id);
146    int
147    (*pf_parse_blocked_frame) (const unsigned char *buf, size_t buf_len,
148        /* TODO: rename third argument when dropping GQUIC */
149                                                lsquic_stream_id_t *stream_id);
150    unsigned
151    (*pf_blocked_frame_size) (uint64_t);
152    unsigned
153    (*pf_rst_frame_size) (lsquic_stream_id_t stream_id, uint64_t final_size,
154                                                        uint64_t error_code);
155    int
156    (*pf_gen_rst_frame) (unsigned char *buf, size_t buf_len,
157        lsquic_stream_id_t stream_id, uint64_t offset, uint64_t error_code);
158    int
159    (*pf_parse_rst_frame) (const unsigned char *buf, size_t buf_len,
160        lsquic_stream_id_t *stream_id, uint64_t *offset, uint64_t *error_code);
161    int
162    (*pf_parse_stop_sending_frame) (const unsigned char *buf, size_t buf_len,
163        lsquic_stream_id_t *stream_id, uint64_t *error_code);
164    unsigned
165    (*pf_stop_sending_frame_size) (lsquic_stream_id_t, uint64_t);
166    int
167    (*pf_gen_stop_sending_frame) (unsigned char *buf, size_t buf_len,
168                                    lsquic_stream_id_t, uint64_t error_code);
169    size_t
170    (*pf_connect_close_frame_size) (int app_error, unsigned error_code,
171                                unsigned frame_type, size_t reason_len);
172    int
173    (*pf_gen_connect_close_frame) (unsigned char *buf, size_t buf_len,
174        int app_error, unsigned error_code, const char *reason, int reason_len);
175    int
176    (*pf_parse_connect_close_frame) (const unsigned char *buf, size_t buf_len,
177                int *app_error, uint64_t *error_code, uint16_t *reason_length,
178                uint8_t *reason_offset);
179    int
180    (*pf_gen_goaway_frame) (unsigned char *buf, size_t buf_len,
181                uint32_t error_code, lsquic_stream_id_t last_good_stream_id,
182                const char *reason, size_t reason_len);
183    int
184    (*pf_parse_goaway_frame) (const unsigned char *buf, size_t buf_len,
185                uint32_t *error_code, lsquic_stream_id_t *last_good_stream_id,
186                uint16_t *reason_length, const char **reason);
187    int
188    (*pf_gen_ping_frame) (unsigned char *buf, int buf_len);
189    int
190    (*pf_parse_path_chal_frame) (const unsigned char *buf, size_t,
191                                                            uint64_t *chal);
192    int
193    (*pf_parse_path_resp_frame) (const unsigned char *buf, size_t,
194                                                            uint64_t *resp);
195#ifndef NDEBUG
196    /* These float reading and writing functions assume `mem' has at least
197     * 2 bytes.
198     */
199    void
200    (*pf_write_float_time16) (lsquic_time_t time_us, void *mem);
201    uint64_t
202    (*pf_read_float_time16) (const void *mem);
203#endif
204    ssize_t
205    (*pf_generate_simple_prst) (const lsquic_cid_t *cid,
206                                                    unsigned char *, size_t);
207    size_t
208    (*pf_calc_stream_frame_header_sz) (lsquic_stream_id_t stream_id,
209                                            uint64_t offset, unsigned data_sz);
210    size_t
211    (*pf_calc_crypto_frame_header_sz) (uint64_t offset, unsigned data_sz);
212    void
213    (*pf_turn_on_fin) (unsigned char *);
214
215    size_t
216    (*pf_packout_size) (const struct lsquic_conn *,
217                                            const struct lsquic_packet_out *);
218
219    /* This returns the high estimate of the header size.  Note that it
220     * cannot account for the size of the token in the IETF QUIC Initial
221     * packets as it does not know it.
222     */
223    size_t
224    (*pf_packout_max_header_size) (const struct lsquic_conn *,
225                    enum packet_out_flags, size_t dcid_len, enum header_type);
226
227    enum packno_bits
228    (*pf_calc_packno_bits) (lsquic_packno_t packno,
229                        lsquic_packno_t least_unacked, uint64_t n_in_flight);
230    unsigned
231    (*pf_packno_bits2len) (enum packno_bits);
232
233    int
234    (*pf_parse_max_data) (const unsigned char *, size_t, uint64_t *);
235    int
236    (*pf_gen_max_data_frame) (unsigned char *, size_t, uint64_t);
237    unsigned
238    (*pf_max_data_frame_size) (uint64_t);
239    /*
240     * Returns number of bytes parsed on success or negative value on error:
241     *  -1  Out of input buffer
242     *  -2  Invalid CID length value
243     */
244    int
245    (*pf_parse_new_conn_id) (const unsigned char *, size_t, uint64_t *,
246                        uint64_t *, lsquic_cid_t *, const unsigned char **);
247    unsigned
248    (*pf_stream_blocked_frame_size) (lsquic_stream_id_t, uint64_t);
249    int
250    (*pf_gen_stream_blocked_frame) (unsigned char *buf, size_t,
251                                                lsquic_stream_id_t, uint64_t);
252    int
253    (*pf_parse_stream_blocked_frame) (const unsigned char *buf, size_t,
254                                            lsquic_stream_id_t *, uint64_t *);
255    unsigned
256    (*pf_max_stream_data_frame_size) (lsquic_stream_id_t, uint64_t);
257    int
258    (*pf_gen_max_stream_data_frame) (unsigned char *buf, size_t,
259                                                lsquic_stream_id_t, uint64_t);
260    int
261    (*pf_parse_max_stream_data_frame) (const unsigned char *buf, size_t,
262                                            lsquic_stream_id_t *, uint64_t *);
263    int
264    (*pf_parse_new_token_frame) (const unsigned char *buf, size_t,
265                            const unsigned char **token, size_t *token_size);
266    size_t
267    (*pf_new_connection_id_frame_size) (unsigned seqno, unsigned cid_len);
268    int
269    (*pf_gen_new_connection_id_frame) (unsigned char *buf, size_t,
270                unsigned seqno, const struct lsquic_cid *,
271                const unsigned char *token, size_t);
272    size_t
273    (*pf_retire_cid_frame_size) (uint64_t);
274    int
275    (*pf_gen_retire_cid_frame) (unsigned char *buf, size_t, uint64_t);
276    int
277    (*pf_parse_retire_cid_frame) (const unsigned char *buf, size_t, uint64_t *);
278    size_t
279    (*pf_new_token_frame_size) (size_t);
280    int
281    (*pf_gen_new_token_frame) (unsigned char *buf, size_t,
282                                        const unsigned char *token, size_t);
283    int
284    (*pf_gen_streams_blocked_frame) (unsigned char *buf, size_t buf_len,
285                                        enum stream_dir, uint64_t);
286    int
287    (*pf_parse_streams_blocked_frame) (const unsigned char *buf, size_t buf_len,
288                                        enum stream_dir *, uint64_t *);
289    unsigned
290    (*pf_streams_blocked_frame_size) (uint64_t);
291    int
292    (*pf_gen_max_streams_frame) (unsigned char *buf, size_t buf_len,
293                                        enum stream_dir, uint64_t);
294    int
295    (*pf_parse_max_streams_frame) (const unsigned char *buf, size_t buf_len,
296                                        enum stream_dir *, uint64_t *);
297    unsigned
298    (*pf_max_streams_frame_size) (uint64_t);
299    unsigned
300    (*pf_path_chal_frame_size) (void);
301    int
302    (*pf_gen_path_chal_frame) (unsigned char *, size_t, uint64_t chal);
303    unsigned
304    (*pf_path_resp_frame_size) (void);
305    int
306    (*pf_gen_path_resp_frame) (unsigned char *, size_t, uint64_t resp);
307    int
308    (*pf_gen_handshake_done_frame) (unsigned char *buf, size_t buf_len);
309    int
310    (*pf_parse_handshake_done_frame) (const unsigned char *buf, size_t buf_len);
311    unsigned
312    (*pf_handshake_done_frame_size) (void);
313    int
314    (*pf_gen_ack_frequency_frame) (unsigned char *buf, size_t buf_len,
315        uint64_t seqno, uint64_t pack_tol, uint64_t upd_mad, int ignore);
316    int
317    (*pf_parse_ack_frequency_frame) (const unsigned char *buf, size_t buf_len,
318        uint64_t *seqno, uint64_t *pack_tol, uint64_t *upd_mad, int *ignore);
319    unsigned
320    (*pf_ack_frequency_frame_size) (uint64_t seqno, uint64_t pack_tol,
321        uint64_t upd_mad /* Don't need to pass `ignore' */);
322    int
323    (*pf_gen_timestamp_frame) (unsigned char *buf, size_t buf_len, uint64_t);
324    int
325    (*pf_parse_timestamp_frame) (const unsigned char *buf, size_t, uint64_t *);
326    int
327    (*pf_parse_datagram_frame) (const unsigned char *buf, size_t, const void **,
328                                                                    size_t *);
329    int
330    (*pf_gen_datagram_frame) (unsigned char *, size_t bufsz, size_t min_sz,
331        size_t max_sz, ssize_t (*)(struct lsquic_conn *, void *, size_t),
332        struct lsquic_conn *);
333    unsigned
334    (*pf_datagram_frame_size) (size_t);
335};
336
337
338extern const struct parse_funcs lsquic_parse_funcs_gquic_Q043;
339extern const struct parse_funcs lsquic_parse_funcs_gquic_Q046;
340extern const struct parse_funcs lsquic_parse_funcs_gquic_Q050;
341extern const struct parse_funcs lsquic_parse_funcs_ietf_v1;
342
343#define select_pf_by_ver(ver) (                                             \
344    (1 << (ver)) & (1 << LSQVER_043)                     ?                  \
345                                         &lsquic_parse_funcs_gquic_Q043 :   \
346    (1 << (ver)) & (1 << LSQVER_046)                            ?           \
347                                         &lsquic_parse_funcs_gquic_Q046 :   \
348    (1 << (ver)) & (1 << LSQVER_050)                            ?           \
349                                         &lsquic_parse_funcs_gquic_Q050 :   \
350    &lsquic_parse_funcs_ietf_v1)
351
352/* This function is gQUIC-version independent */
353int
354lsquic_gquic_parse_packet_in_begin (struct lsquic_packet_in *, size_t length,
355                int is_server, unsigned cid_len, struct packin_parse_state *);
356
357int
358lsquic_Q046_parse_packet_in_short_begin (struct lsquic_packet_in *, size_t length,
359                int is_server, unsigned, struct packin_parse_state *);
360
361int
362lsquic_Q046_parse_packet_in_long_begin (struct lsquic_packet_in *, size_t length,
363                int is_server, unsigned, struct packin_parse_state *);
364
365int
366lsquic_Q050_parse_packet_in_long_begin (struct lsquic_packet_in *, size_t length,
367                int is_server, unsigned, struct packin_parse_state *);
368
369enum quic_frame_type
370lsquic_parse_frame_type_gquic_Q035_thru_Q046 (const unsigned char *, size_t);
371
372extern const enum quic_frame_type lsquic_iquic_byte2type[0x40];
373
374size_t
375lsquic_calc_stream_frame_header_sz_gquic (lsquic_stream_id_t stream_id,
376                                                    uint64_t offset, unsigned);
377
378size_t
379lsquic_gquic_packout_size (const struct lsquic_conn *,
380                                            const struct lsquic_packet_out *);
381
382size_t
383lsquic_gquic_packout_header_size (const struct lsquic_conn *conn,
384                enum packet_out_flags flags, size_t unused, enum header_type);
385
386size_t
387lsquic_gquic_po_header_sz (enum packet_out_flags flags);
388
389size_t
390lsquic_gquic_packout_size (const struct lsquic_conn *,
391                                            const struct lsquic_packet_out *);
392
393size_t
394lsquic_gquic_po_header_sz (enum packet_out_flags flags);
395
396/* This maps two bits as follows:
397 *  00  ->  1
398 *  01  ->  2
399 *  10  ->  4
400 *  11  ->  6
401 *
402 * Assumes that only two low bits are set.
403 */
404#define twobit_to_1246(bits) ((bits) * 2 + !(bits))
405
406/* This maps two bits as follows:
407 *  00  ->  1
408 *  01  ->  2
409 *  10  ->  4
410 *  11  ->  8
411 *
412 * Assumes that only two low bits are set.
413 */
414#define twobit_to_1248(bits) (1 << (bits))
415
416#define ECN_COUNTS_STR  " ECT(0): 01234567879012345678790;" \
417                        " ECT(1): 01234567879012345678790;" \
418                        " CE: 01234567879012345678790"
419#define RANGES_TRUNCATED_STR " ranges truncated! "
420
421#define MAX_ACKI_STR_SZ (256 * (3 /* [-] */ + 20 /* ~0ULL */ * 2) \
422                    + sizeof(ECN_COUNTS_STR) + sizeof(RANGES_TRUNCATED_STR))
423
424void
425lsquic_acki2str (const struct ack_info *acki, char *, size_t);
426
427void
428lsquic_turn_on_fin_Q035_thru_Q046 (unsigned char *);
429
430enum packno_bits
431lsquic_gquic_calc_packno_bits (lsquic_packno_t packno,
432                        lsquic_packno_t least_unacked, uint64_t n_in_flight);
433
434unsigned
435lsquic_gquic_packno_bits2len (enum packno_bits);
436
437int
438lsquic_merge_acks (struct ack_info *dst, const struct ack_info *src);
439
440#endif
441